Products of the reaction of dialkyl ketenes with dihydropyrans



3,161,348 PRODUCTS OF THE REACTIUN 6F DEIALKYL KETENES WITH DIHYDRUPYRANS James C. Martin, Kingsport, Tenn, assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Aug. 26, 1960, Ser. .No. 52,029

9 Claims. (Cl. 260-3452) 1 This invention relates to certain novel chemical compounds, namely, the 2-oxa-8,S-dialkylbicyclo[4.2.0] octan- 7-ones, and derivatives thereof and to the method of prep :aration' of such compounds.

The new compounds of the invention are prepared by the reaction of dialkyl ketenes with dihydropyrans. The following general equation illustrates the reaction:

side reaction of ketcne dimerization. Reaction temperatures from C. to 150 C. can be used, the higher temperatures being preferred for'the less reactive intermediates. The reaction can be carried out with or without solvents. Suitable solvents are those that function as 'solvents for the reactants and the products but do not react with either. Typical solvents are: aliphatic esters,

ethers, chlorinated aliphatic hydrocarbons, nitriles, and.

aliphatic and aromatic hydrocarbons. After completion of the reaction the novel compounds of the invention are separated from the solvent, unconverted reactants, etc., by distillation;

Ketenes that can be used in the method of the invention are indicated by the reaction equation above; namely, compounds of the structure, (R) C=C=O, wherein the substituents, R, are alkyl groups of 1 m4 carbon atoms or are hydrocarbon groups which, with the carbon atom xtowhich they are attached, form a 5 or 6 membered carbocyclic ring. Examples include diamethylketene, ethylmethylketene, diethylketene, butylethylketene, di-n-propylketene, diisobutylketene, di-n-butylketene, and carbocycl-ic ketenes. such .as tetramethyleneketene and pentarnethyleneketenei uThe ketenes can be prepared by the method described in copending application of ,Hasek et aL, Serial .No. 841,961, filed September 24, 1 959. i i

Dihydropyrans suitable for the method or" the inven tion are also indicated by the equation above and have the general formula:

wherein R is hydrogen or a C to C alkyl group and R is hydrogen, CHO or -OR. Examples include dihy dropyran, 3,4-dihydro-ZH-pyran-Z-carboxaldehyde, 3,4- dihydro-2,5-dirnethylcarboXaldehy-de, 3,4 dihydro-Z-eth- 1 United States Patent 2 oxy-ZH-pyran, 3,4 dihydro-2-ethoxy-S-methyl-ZH-pyran, and 3,4-dihydro-2ethoXy-4-methyI-ZH-pyran.

The novel ketones of the invention are useful mainly as chemical intermediates which lead to various products of important utility. One such use consists of hydrogenating the novel ketone to form the corresponding alcohol and preparingan ester of the alcohol and a carboxylic acid, such as azelaic acid. The resulting esters are valuable as plasticizers for various polymer compositions. Another use of the novel ketones consists of reacting the new compounds with an aromatic diamine, such as a p-phenylene 'd-iamine, and hydrogenating the resulting di-Schiifs base to an N,N'-substituted p-phenylenediarnine. The resulting compounds are valuable as antioxidants for organic materials such as gasoline and rubber. a i

The following examples illustrate the preparation of the novel ketones of the invention.

Example 1 About 2 moles of ethylmethylketene was added over. a period of 1 hour to 252 g. (3 moles) of dihydropyran. The reaction solution was stirred for 6 hours and maintained at 20-25 C. by rneansof a water bath. Distillation of the reaction solution through, an, 18 in. packed column gave 1.1 moles of recovered dihydropyran and 246 g. (71%) of 2-oxa-8-ethyl-8-rnethyl-bicyclo[4.2.0]- octane-7-one, boiling point, 96-97 C. (11 mm). Analysis-Calculated for C I-1 30 C, 72.5 ,H, 9.9. Found: C, 72.4; 11,99.

Example 3 Into a solution of 384 g. (3.() moles) of 3,4-dihydro- 2-ethoxy-2H-pyran in 1000 ml. of benzene was passed approximately 105 g. (1.5moles) of dimethylketene over a period of 1 hour. The reaction temperature was kept at 2530 C. by means of a water bath. The reaction solution was allowed to stand at room temperature for 20 hours. Analysis by gas chromatography showed unreacted 3,4 dihydro-2-ethoxy-2H-pyran, dimcthylketene dimer and a large peak attributed to the product. Distillation of the reaction solution through an18-in. packed column gave 230 g. (1.8moles) of unreacted 3,4-d i hydro- Z-ClllQXY-ZH-PYPQH, some "2,2,4,4-tetrarnethyl-1,3cyc1obutancdione, and 198.0 g.(35% yield based on 3,4-dihydro-2-ethoXy-2Hpyran' consume-d the reaction) of boiling point116 C. ('13 mm). This material solidified rapidly; An 'analytical'sample was recrystallized from ethanol to give a product melting at 55 C. Analysis. Calculated forCj H O C, 66.7; H,-9.1. Found: C, 66.5;H, 9.2. a i

- Example4 tan-7-one, boiling point 121 C. (13 mm).

' with a Dean-Stark tube.

for 24 hours.

solution of '15 g.

The following examples illustrate the preparation of valuable derivatives of the novel ketones and uses of such derivatives.

- Example A solution of 80 g. (0.52 mole) of 2-oxa-8,8-dimethylbicyclo[4.2.0]octan-7-one, as prepared in Example 1, in 250 ml. of ethanol was hydrogenated over g. of 5% ruthenium on carbon in a stainless steel 100 C. and 3,000 p.s.i. of. hydrogen pressure. After the autoclave was cooled and vented, the contents were filtered to remove the catalyst. The filtratewasdistilled through an 18-inch packed column to give 67.2 g. (83%) of 2-oxa- 8,8 dimethylbicyclo[4.2.0]octan 7 ol, boiling point 100-103" C. (10 mm), 11 l.4822.. Analysis.Calculated for 0 11 0 C, 69.2; H, 10.3. Found: C, 69.3; H, 10.3. The 3,5-dinitrobenzoate of this alcohol was prepared by the usual methods and melted at 131-133 C.

Analysis-Calculated for C16H13N2O7I C, 54.8; H, 5.2; k-N,-8.0. Found: C, 54.7; H, 5.0; N, 7.7. 7

Example 6 A mixtur'e of 94 g. (0.5 mole) of'azelaic acid, 170 g.

bis(8,8 dimethyl 2 oxa bicyclo[4.2.0]octan 7 o1 ester, boiling point 120-129 C. (p), n -1.4833.

Analysis.-Calculated for C2'7H4406: C, 69.9; H, 9.5; sapon. equiv., 232. 7 equiv., 232.

Found: C, 69.4; H, 9.3; sapon.

Example 7 autoclave at 'It was washed with sodium.

Sixty parts of polyvinyl chloride and 40 parts of azelaic acid, .bis'( 8, 8-dimethy1-2-oXa-bicyclo [4.2.0] octan-7-ol ester, as prepared in Example 6, were mixed on hot rolls, v

V i and the mixture wasextruded to give a sheet 0.006 inch in thickness. This sheet was quitestrong and flexible and itshowed substantially no loss of plasticizer when exposed to soapy water for 96 hours. There was also very little loss of plasticizerwhen the film was heated at 100 C.

. A solution of 77 g. (0.5 mole) of 2-oxa'-8,8-dimethyl-bicyclo[4.2.0]octan-7-one, as prepared in Example 1, 21.6 g. (0.2-mole) of p-phenylenediamine, and 0.5 g. of p-tolue'n'esulfonic acid in 250ml. of toluene was refluxed for 12 hours under a 10411011 column'equipped with a Dean- 'Stark tube. A; total of 6.5 ml. of water was removed.

Upon cooling, a yellow solid pr eciptat'ed.v This was iso- 3 lated by tiltnation 'and' weighed 42.3 g. Recrystallization from benzene gave product having M.P. 199-201.?- C fAnalysis-Calculated for C24H N O C, 75.9; H, 8.4; N, 7.4. 7 Found: (3,175.2;1-1, 9.0; N, 7. 4,

Example 9 nurnon carbon ina stainless steel autoclave at 160C. and 1,500 psi. of hydrogen pressure. After the autoclave was cooled and vented,'the contents were filtered to remove catalyst- .;Evaporation of the filtrate yielded of the product'of Example 8 in 75. ml. of ethanol washydrogenated over 5 g. of 1% platicompounds of the formulae:

V wherein R is a member of the group consistingof hydro genand'allgyl groups of from 1 to 4 carbon atoms; R isa member of the group consisting of hydrogen, CHO',,and

a dark, high boiling residue. When 0.01 part of thisma- 1 terial was added to parts of cracked gasoline, it was K found that the resulting solution had much better resistance to oxidation than did the unmodified gasoline. This test was carried out at 211.6 P. under 100 p.s.i. of oxy gen in a stainless steel bomb.

Although the invention has ments thereof, it will be understood that variations and modifications can be efiected Within the spirit and scope of the invention as described hereinabove andas defined in the appended claims. 7 I claim: I 1. 2-oxa-8,S-dimethylbicyclo [4.2.0]octan-7-one. 2. 2-oxa-8-ethyl-S-methylbicyclo[4.2.0] octan-7-one. 3,. 3 ethoxy 2 oxa 8,8 dimethylbicyclo[4.2.0]- octan-7-one.

4. 3 etho'xy 2 oxa 6,8,8 trimethylbicyclo[4. 2.0]

octan-7-one.

5. The method which comprises reacting a dihydropr'an of the structure:

wherein R is a member of the group consisting of hydrogen and alkyl groups of from 1 to 4 carbon atoms; and

R is a 'member of the group consisting of hydrogen,

-CHO, and -OR; with a dialkyl ketene of the structure:

\O=C=O wherein R a member of the group consisting of alkyl groups of from 1 to 4 carbon atoms and alkylene radicals which, together with the carbon atom of the ketene radical to which they are attached, form a carbocyclic ring of '5 to 6 carbon atoms;

6. The method according to cl airn5 in which thereac- I tion is carried out at a temperatureof 0 to C. in the presence of an inert solvent and employing an excess of the dihydropyran.

7. 2-0xa-8,8-dimethylbicyclo[4.2.0]octanJ-ol.

. 8. Bis(8,8 dimethyl 2 oxab icy clo[4.2.0]octana7-yl) azelate. V

9'. A. compound selected from the group consisting of -OR; and R isamember of'the' group consisting of alkyl groups of from 1t'o'4; carbon atoms andalkylene' radicals which, together with the carbon atom of the fourmember ring to which they are attached, form a saturated carbocyclic ring of 5 to 6 carbon atoms.

References Cited in. the file of this-patent Blomquist et-aL: lour. AmpChem. See. pages 2098-2100 (1951). I

been described in consider abledetail with reference to certain preferred embodivolume 73,1 

9. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS OF THE FORMULA 